Gear drive for rolling mill



Aug, l7, 1956 Filed May 3l. 1950 GEAR DRIVE H. UEBING FOR ROLLING MILL 3 Shees-Sheet l HINRICH UEB me ATTGE/VEX Aug. m 1956 H. UEBING GEARDRIVE FOR ROLLING MILL 5 Sheelcs-Shee Filed May 31, 1950 NVENTOR. HElNRmH U EBM MTTWMEV Allg- 7, 1955 H. UEBING 2,757,556

GEAR DRIVE RoR ROLLING MILL GEAR DRIVE FOR ROLLING MILL Heinrich Uebing, Lintorf, near Dusseldorf, Germany, assignor to Friedrich Kocks G. 111.11. H., Dusseldorf. Germany, a corporation of Germany The invention relates to rolling mills and relates more particularly to mills for use in rolling and sizing tubes.

The invention has among its objects the provision of such a rolling mill capable of exerting a pull onto the work piece in addition to the roller working, for simultaneously sizing the outside diameter of tubes as well as sizing the wall thickness thereof.

It is another among the objects of the invention to provide for selective and stepless variation of the speed of the rollers of the various rolling stages,`and also to provide for a variable rate of change of the speed assigned to the various stages.

Further objects and advantages of the invention will be set forth in part in the following specification and in part will be obvious therefrom without being specifically referred to, the same being realized and attained as pointed out in the claims hereof.

With the above and other objects of the invention in view, the invention consists in the novel construction, arrangement and combination of various devices, elements and parts, as set forth in the claims hereof, certain embodiments of the same being illustrated in the accompanying drawings and described in the specification.

In the accompanying drawings,

Fig. 1 is a plan view of a rolling mill in accordance with the invention;

Fig. 2 is a schematic and elevational View as seen in direction 2 2 of Fig. 1;

Fig. 3 is a sectional view taken along line 3 3 of Fig. l;

Fig. 4 is a plan view, in certain respects, similar to that of Fig. l, but embodying a modification;

Fig. 5 is a sectional detail View, taken on line 5-5 of Fig. 4, on an enlarged scale;

Fig. 6 is a fragmentary sectional View taken on line d-6 of Fig. 5; and

Fig. 7 is a graph showing the revolving speeds plotted for the mill stages. n

In Fig. 1, there is provided a mill, generally indicated at 10. The mill has a series of stages, eighteen being shown and numbered 11 through 28, respectively. In the embodiment shown in Fig. 1, alternateistages are driven from opposite sides; the odd numbered stages, 11, 13, 1S 27, are driven by a power drive generally designated 29 that is situated at the left side of the stages, and the even numbered stages 12, 14 28, are driven by a power drive 31 that is located at the right side of the stages. The terms left and right are being used not only because they indicate the sides of the illustration of Fig. 1, but also because of the flow of the work piece through the stages, which takes place in the direction of the arrow 30.

However, the arrangement that different stages are powered from different sides is not always necessary, and has been made only for the purpose of distributing the power drive elements in a short space for providing a minimum overall length of the mill. As shown in Fig. 4, all the stages may be driven from one side, and in `this modification a proper distribution has been made by olfnited States Patent O 2,757,556 Patented Aug. 7, 1956 2 setting in a vertical direction certain of the elements, as best illustrated in Fig. 5.

Returning to the description of the embodiment shown in Figs. 1-3, each stage is provided with three rollers 32, 33 and 34, and each of the rollershas a. concave peripheral surface in accordance with the sizing diameter of the tube at the particular stage. The rollers 32, 33, and 34 are oifet against each other for and the rollers of the adjoining stage (shown in broken lines in Fig. 3), are offset against the rollers of the other stage for 60; thereby, the tube will be gripped from different angles as it proceeds from stage to stage.

The rollers 32 and 34 carry each a shaft 36 that is provided with a bevel gear 37 in mesh with a gear 33 of equal size and mounted on a shaft 39 which is journalled in a gear 41 of a trai`n`42 of intermeshed gears of equal size. The roller 33 carries a shaft 43 that is journalled in a gear 44 of said train 42. One of said gears, designated 46 of said train 42, is carried at the end of a shaft 47 that provides the connection of the power drive. Since the gears of the train 42 are provided with the same pitch diameter, and the bevel gears 37 and 3S are also at the ratio 1: l, the shaft 47 will transmit revolving speed to the rollers 32, 33 and 34 equally, and they will rotate at the same speed.

Since the stage shown at Fig. 3 is driven from the right hand side power drive 31, that drive will now be described, it being understood that the opposite drive 29 is similar thereto except for the transmission ratios as will be disclosed in detail later on.

The power drive 31 is powered by an electric motor 48, that is interconnected to an electric source (not shown). The motor 4S drives a shaft 49 that carries a differential gearing mechanism 51. A shaft 52, in alignmeut with the shaft 49, extends from the differential mechanism 51 and, when the housing 53 of the mechanism 51 is at rest, the planetary gearings 54 and 56 thereof will only revolve around their axes, and rotation of the shaft 49 will be transmitted without change of speed, but in opposite direction, to the shaft 52. The shaft 52 carries a series of bevel gears, designated 1201 for the second stage 12, 1401 for the fourth stage 14, 1601, 1001 2301. These shaft borne bevel gears mesh with bevel gears at right angle thereto and correspondingly designated 1202, 1402 2802. The ratios of transmission between these bevel gears change, the lowest transmission being at the earliest stage 11, and the highest transmission at the last stage 28. Thus, of the shaft borne gears, the gear 1201 is the smallest and the gear 2301 is the largest for the poweridrive 31, and conversely, the gear 1202 the largest at that side and the gear 2802 the smallest. Each of the last named bevel gears operates the rollers of a stage, and carries a shaft 57..`

A differential gear mechanism is borne by each of the shafts 57, and each shaft 57 has opposite bevel gears, a bevel gear 53 (Fig. 3) being mounted on the shaft 57 and a bevel gear 59 mounted on the previously mentioned roller operating shaft 47. The bevel gears 5S and 59 are in mesh with planetary gears 61 and 62 that are journalled in a revoluble housing 63. When the housing 63 is at rest, there is a direct, though inverted, connection between the shafts 57 and 47 `in the`direction of power transmission.

Each housing 63 carries a gear wheel, but the diameter of each of these wheels is different from those of the other housings, the designations being `1203, for the second stage 12, 1403 2803. i

There is a provision for changing the normal speed of the shaft 52 at a step-less and selective rate, by revolving the housing 53 of the shaft differential 51. Such a change will be transmitted at `the the various stages, since the bevel" gears 1201 and 1202,

same rate of change to' 1401 and 1402 2801 and 2802 are always in mesh and have a xed ratio. However, there is also a provision to change the speed of therollers of the various stages at an unequal rate of change for the different stages. This is done by revolving the housings 63 at a different speed for each stage.

The two changes discussed, namely, those brought about by revolving the housing 53 and those brought about by revolving simultaneously, though at different speeds, all the housings 63, are brought about by a single means, illustrated in Figs..l and 2,. It willbe understood, however, that this is done by way of illustration only, it being well conceivable thatzseveral means instead fl a single one be employed, and no limitation is intended by the illustrated exemplification.

The means referred to is an auxiliary power drive gcnerally indicated 64. It comprises an auxiliary motor 66 that drives a Series of intermeshed gears 67, 68 and 69. The gear 6,9 concentrically carries on a shaft 70 a small gear 71 that is in mesh with a large gear 72 which is mounted on and is arranged to revolve the housing of the differential gear mechanism 51. The shaft 70 extends parallel to and below the shaft 2 and, like the shaft 52 carries a similar series of bevel gears meshing with bevel gears at right angle thereto, comparable to the gear pairs 1201 and 1202 2801 and 2802. l

The drivenbevel gears are mounted on shafts 73 that are parallel to the shafts 57, and each shaft 73 carries a straight gear wheel, for instance, the gear wheel 1604 illustrated in Fig. 3 (showing the sixth stage 16). Each of these last named gears is in mesh with a gear mounted on a housing 63, for instance, at the sixth stage (Fig. 3) with the gear 1603.

When the auxiliary motor 66 operates, it will drive the gears 67, 68 and 69 and therewith the shaft 70 and the gear 71. It is advantageous to provide for releasable keying of the gear 71 on the shaft 70, and also for the split coupling of the shaft 70 before it reaches the first bevel gear (not shown), in order to enable separate or tied operation, respectively, of the shaft differential 51 and of the stage differentials 63.

The power drive 2,9 is similar to the above described power drive 31, and where similarity exists the same reference numerals have been used. The left auxiliary drive is generally indicated at 65. However, the bevel gears 1101, 1301 2701 on the shaft 5 2, and the bevel gears 1102, 1302 2702 differ from the corresponding gears on the right hand side in size, since otherstages and consequently the transmissions of different speeds are involved. Consequently, the size of the right hand gear 1201 is between the sizes of the gears 1101 and 1301, and likewise the size of the gear 1202 is between those of the gears 1102 and 1302, as Will be readily understood.

The housings 63 on the left side are provided with gears 1103, 1303 2703 that, owing to their being assigned to different stages as compared to the right side, have different sizes as compared to the gears of the right side housing. Similarly, the gear 1504 of the shaft 73 (left side of Fig. 3) also is different in size from the gear 1604 (right side, Fig. 3).

The operation of the above described embodiment is, as follows. The tube, which may be, for instance of a size having a three inch outside diameter and a wall thickness of 1A; of an inch is inserted in the mill in the direction of the arrow 30 and into the first stage. ,11 thereof. At the stage 11, the rollers 32, 33 and 34 which are calibrated for that dimensioned tube, will feed in the tube at a linear speed of about inches per second. In the assumed example the discharge size of the tube may be for instance, one inch outside diameter and 3,@2" wall thickness, and emerge from the last stage 28 of the mill at a speed of 100 inches per second.

The rotational speed of the rollers Will be commensurate with these entry and exit speeds, with a steady,

though not necessarily linear, speed increase between the first and last stages (see Fig. 7).

It is preferable to make the rolling speed increase slightly larger than the natural speed increase of the work piece that is brought about by the reduction in width and consequent increase in the length of the work piece. The speed of the rollers of the individual stations is so arranged that the speed increase of succeeding stations is in excess of the feeding speed of the work piece at which it emerges from the preceding stage, in order to provide a pull for predetermined, selectively adjustable, sizing of the wall thickness in addition to the conventional sizing of the outside diameter of the tubular work piece.

A different arrangement is shown in Figs. 4, 5, and 6. In this modification, the rollers of all the stages are operated from one side, the left side having been selected for the purpose of exemplication. Those parts which are similar to the parts of the `preceding embodiment bear the same reference numerals.

There are. again eighteen stages provided in the exemplitication, numbered 1,1 through ,28, and. the work piece is fedinto the mill, in direction 30 at the iirst stage 11 that operates at theslowest revolving speed of its rollers 32 33 and 34, and is discharged from the highest speed stage 28. The motor 48,'and the auxiliary motor 66 are again found in this embodiment, and the motor 48 again drives a shaft 52 and carries a differential mechanism 51 for control of the speed of the shaft 52.

The shaft 52 carries a series of nine bevel gears, one for each alternate station, and designated 1201, 1401, 1601 2801. Each bevel gear of the shaft is permanently in meshwith a. bevel gear at right angle thereto, indicated at 1.202, 1402 2802. Each of the last named gears is mounted on a shaft 82 for driving the rollers of the even-numbered stages, and between these shafts 82 there are provided similar shafts designated 81 for driving the rollers of the odd-.numbered stages. Each shaft 81 carries a gear l83, and each shaft 81 a gear 84 in mesh with the gear 83. The gears 84 and 83, respectively, have a pitch ratio in accordance with the predetermined speed increase of two succeeding stages. The gears 83 and 84 enable the driving of all of the. eighteen stages from one side, by directly driving only alternate stages and transmitting the power, indirectly, therefrom to the remaining stages therebetween. It would, of course, be possible to drive all of the shafts 81 and 82 directly from the power shaft 5,2, but the instant arrangement of directly operating only alternate shafts 82, has the advantage of saving space to reduce the overall length of the rolling mill, without sacrificing the desirable thicknesses of the transmission elements involved in the reduced available space. However, while this is a preferred arrangement, it will be undeIStQod that n0. limitation of either the scope of invention nor of protection is intended thereby, save as indicated in the claims, appended hereto.

Each of the shafts 81 and 82 carries the housing of a differential mechanism, the shafts 81 carrying mechanisms 85, and the shafts 82 carrying mechanisms designated 86. For purposes of space arrangement, the housings of the mechanisms 86 are placed invertedly relative to the housings ofthe mechanisms S5. Each housing carries a hollow shaft 89, and carries at the end of the hollow shaft a gear l87, and at the other end a gear 88. An exception is the housing 8S of the first stage 11 which carries only one gear 87. The gears 87 and 88 form a gear train, each gear 88 of one mechanism being in mesh with a gear 87 of the adjoining differential mechanism. The ratios of pitch of these gears S7 and 88 are designed in accordance with the predetermined rate of change of revolving speed of the rollers of the individual stages when the auxiliary drive is actuated, that normally, however,v is at rest.

This train `of gears 87 and 88 replaces, and has the same function as, the auxiliary shaft and bevel gears operated thereby of thc previously described embodiment (Figs. 1-3).

The housings of the shafts 81 and 82 are olf-set vertically from each other for the purpose of saving space to provide a minimum length for the entire rolling mill, as best shown in Fig. 5.

The auxiliary motor 66 (Fig. 4) drives a bevel gear 91 that meshes with a bevel gear 92, and the latter is mounted on the housing of the differential mechanism S6 of the last station 28.

The operation of this modification is like that of the previous embodiment, but the shaft 52 drives only the shafts 82 of alternate stages and the power is transmitted therefrom to the intermediate shafts 81 by pairs of meshing gears 83 and 84. The auxiliary drive 64 include.; a pair of bevel gears 91 and 92 receiving the power from the auxiliary motor 66, and a continuous train of gear pairs 87 and 88 to transmit revolving energy to the housings of the differential mechanisms.

Certain of the advantages of the invention have already been herein referred to. It may be useful, however, to allude particularly at this point to the double speed control each providing for step-less and adjustable variation of the speed assigned to the rollers of the individual stages. An example, illustrated in Fig. 7, may serve to bring out this more fully.

It is assumed that the rollers of the rst stage 11 were revolving at 50 R. P. M. and the rollers of the last stage 28 at 250 R. P. M., when the auxiliary drive 64 is at rest. The gears on the housings of the differential mechanisms (1103, 1203 2803 of Fig. l and 87 and 88 of Fig. 4) may be so dimensioned that upon operation of the auxiliary mechanism the rollers of the first stage revolve at a speed of 51 R. P. M., for example, and the lrollers of the last stage at 400 R. P. M. Thus, the increase of the first stage is 2% whereas the increase of the last stage is 60%. Decrease, is of course, also possible by operation of the auxiliary drive. In Fig. 7, the curve of the speeds assigned to the stages while the auxiliary drive is at rest is indicated at 93, and thc change after the auxiliary drive is operated for increase is shown at 94 and for decrease at 95.

It will be apparent to those skilled in the art that the novel principles of the invention disclosed herein in connection with specific exemplifications thereof will sug gest other various modifications and applications of the same. It is accordingly desired that in construing the breadth of the appended claims they shall not be limited to the specific exemplifications of the invention described herein.

Having thus described the invention, what I claim as new and desire to be secured by Letters Patent, is as follows:

1. In a rolling mill of the continuous type for the reduction of the outside diameter of tubes, by exerting rolling action upon the outer surface of the tube, having a plura1- ity of successive aligned roller stages each. comprising one set of rollers adapted to be operated at a variable circumferential speed, in combination, a power drive for each roller stage comprising at least one main shaft drivingly connected to a power source and rotated thereby, a set of gear trains, each gear train being in positive driven connection with said main shaft and one of said roller stages for simultaneous energization of all of said roller stages from said main shaft, said gear trains constituting a first fixed sequence `of different gear ratios, differential gear units one each between said main shaft and one of said roller stages and drivingly interconnecting said main shaft and each of said roller stages, an auxiliary power drive in positive driving connection with each differential gear units, auxiliary gear trains one each drivingly connecting said auxiliary power drive and one of said differential gear units, said auxiliary gear trains constituting a second fixed sequence `of different gear ratios differing from the first fixed sequence, whereby the rollers of each roller stage will have a circumferential speed impressed by said first and second fixed gear train sequences.

2. In a rolling mill as claimed in claim l, adjusting means disposed between said power source and said main shaft and operable for a stepless varying of the rotational speed of said main shaft, and means between said auxiliary drive and said adjusting means `operable for superposing on the energy supplied to said main shaft from said power source an additional energy supply delivered from said auxiliary power drive.

3. In a rolling mill as claimed in claim 2, said adjusting means including a main differential gear, said auxiliary power drive comprising an auxiliary shaft, said adjusting means and auxiliary shafts being drivingly connected to said main differential gear.

References Cited in the le of this patent UNITED STATES PATENTS 351,841 Lenox Nov. 2, 1886 1,376,015 Hamilton Apr. 26, 1921 1,466,642 Crook Aug. 28, 1923 1,594,394 Weston Aug. 3, 1926 1,594,395 Weston Aug. 3, 1926 1,594,396 Weston Aug. 3, 1926 1,784,545 Schiebuhr Dec. 9, 1930 1,939,113 Ferris Dec. 12, 1933 1,964,188 Von Karabetz `lune 26, 1934 2,131,541 Pease Sept. 27, 1938 2,227,801 Trofimov Ian. 7, 1941 FOREIGN PATENTS 311,942 Germany May 6, 1919 792,397 France Dec. 30, 1935 

